Aquarium station is an underground rapid transit station on the MBTA Blue Line in Boston, Massachusetts, United States. It is located under State Street at Atlantic Avenue on the eastern edge of Boston's Financial District near Boston Harbor. The station is named for the nearby New England Aquarium. It is adjacent to Long Wharf, which is used by two MBTA Boat lines. The station has two side platforms serving the two tracks of the Blue Line; an arched ceiling runs the length of the platform level. With the platforms 50 feet (15 m) below street level, it is the second-deepest station on the MBTA system (after Porter station).